Anatomical evidence for multiple pathways leading from the rostral ventrolateral medulla (nucleus paragigantocellularis) to the locus coeruleus in rat.
Using retrograde transport of Fluoro-Gold (FG) combined with immunofluorescence for phenylethanolamine-N-methyltransferase (PNMT), we have examined afferents to the nucleus locus coeruleus (LC) from the rostral ventrolateral medulla (nucleus paragigantocellularis; PGi) in rats sustaining lesions of the medullary adrenergic bundle (MB). In lesioned rats, very few adrenergic LC-projecting neurons persist in the PGi ipsilateral to the lesion, representing a 90% decrease in comparison to non-lesioned animals. These results indicate that almost all adrenergic input to the LC from C1 neurons in PGi is conveyed by the MB. In contrast, the number of non-adrenergic LC afferent neurons in the PGi ipsilateral to the lesion only decreased by 48% after such lesions. Thus, this pathway also provides non-adrenergic projections to LC from PGi, but many of these are conveyed by other route(s) as well.
Astier
B
B
Laboratoire de Neuropharmacologie, CNRS UMR 105, Faculté de Pharmacie, Université Claude Bernard, Lyon, France.
Van Bockstaele
E J
EJ
Aston-Jones
G
G
Pieribone
V A
VA
D000818:Animals; D002452:Cell Count; D005455:Fluorescent Antibody Technique; D007150:Immunohistochemistry; D008125:Locus Coeruleus / Q000033:anatomy & histology*; D008297:Male; D008526:Medulla Oblongata / Q000033:anatomy & histology*; D009434:Neural Pathways / Q000033:anatomy & histology; D009474:Neurons / Q000737:chemistry; D051381:Rats; D011919:Rats, Inbred Strains